A senior U.S. State Department official on June 18 played down an announcement by Russia that it will add tens of new intercontinental ballistic missiles to its nuclear arsenal.

Victoria Nuland, U.S. assistant secretary of state for European affairs, told reporters on a visit to the Czech capital, Prague, "Those kinds of announcements when made publicly like that obviously have a rattling effect."

"When we look at what is actually happening inside Russia, it is far less dramatic," she said, commenting on Russian President Vladimir Putin's announcement of the plan on June 16.

Putin said June 16 that Russia would add more than 40 new intercontinental ballistic missiles to its nuclear arsenal this year.

But on June 17, the Kremlin said Russia does not want to enter a costly new arms race with the West, saying it would hurt the country’s economy.

"We are against any arms race because it naturally weakens our economic capabilities,” presidential aide Yury Ushakov said on June 17. “In principle we are against it."